Slurry pump of oil-diaphragm type

ABSTRACT

In a riser portion of the slurry connecting pipe between the valve box and the diaphragm chamber of an oil-diaphragm slurry pump having a plunger pump, there is installed a pipe part of large cross section having an interior of a volume greater than the suction displacement of the plunger pump and of a configuration such as to provide abruptly changing cross sectional area with respect to slurry flow therein, whereby turbulent flow, eddy flow or vortices are continually formed in the slurry during pump operation thereby to prevent settling of solid particles.

United States Patent i191 Seki et al.

[ SLURRY PUMP OF OIL-DIAPHRAGM TYPE [7 5] Inventors: Kazunori Seki;Toshio Kazama, both of Nagaoka, Japan [73] Assignee: Tamagawa KikaiKinzoku Kabushiki Kaisha, Tokyo-to, Japan [22] Filed: Apr. 19, 1971 [21]Appl. No.: 134,946

[30] Foreign Application Priority Data Jan. 28, 1971 Japan 46/2600 [52]US. Cl. 417/92, 417/430, 417/900 [51] Int. CL... F04f 11/00, F04b 21/00,F04b 15/02 [58] Field of Search 417/900, 92, 93,

[5 6] References Cited UNITED STATES PATENTS 3,241,496 3/1966 Imai et a1417/98 [111 3,740,166 51 June 19, 1973 FOREIGN PATENTS OR APPLICATIONS1,193,368 5/1965 Germany 417/99 Primary ExaminerCarlton R. CroyleAssistant ExaminerRichard E. Gluck Att0meyRobert E. Burns and EmmanuelJ. Lobato [57] ABSTRACT In a riser portion of the slurry connecting pipebetween the valve box and the diaphragm chamber of an oildiaphragmslurry pump having a plunger pump, there is installed a pipe part oflarge cross section having an interior of a volume greater than thesuction displacement of the plunger pump and ofa configuration such asto provide abruptly changing cross sectional area with respect to slurryflow therein, whereby turbulent flow, eddy flow or vortices arecontinually formed in the slurry during pump operation thereby toprevent settling of solid particles. 1

2 Claims, 2 Drawing Figures Patented June 19, 1973 3,740,166

FIG. 2

SLURRY PUMP OF OIL-DIAPHRAGM TYPE BACKGROUND OF THE INVENTION Thisinvention relates generally to slurry pumps of the oil-diaphragm typeand more particularly to a slurry pump of this type with a new andadvance communication path between the valve box and the oil-diaphragmchamber of the pump.

Slurry pumps with which this invention is concerned are of the classdescribed in Japanese Patent Publication No. 12131/1960, U.S. Pat. No.3,241,496, patented Mar. 22, 1966, British Pat. No. 1,187,912, patentedAug. 12, 1970, and South African Pat. No. 68/0753, patented May 30,1969.

In general, liquids pumped by slurry pumps contain, in addition to solidparticles, air bubbles in the form of minute particles, which give riseto various severely deleterious effects on the pump performance.Particularly in a slurry pump of the oil-diaphragm type, theoildiaphragm chamber contains slurry with a large quantity of solidparticles and a diaphragm oil, and the slurry connecting pipe betweenthe valve box and the diaphragm chamber is also filled with the slurry.

Consequently, the liquid resistance is higher than that in other pistonpumps and becomes a cause of liquid column separation which gives riseto loud noise and vibration in the mechanical structure of the pump.Furthermore, when air accumulates within the oildiaphragm chamber, itcauses a drop in the delivery capacity, of the pump and impairment ofpumping perfor- 'mance in continuous operation over a long period.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an oil-diaphragm slurry pump in which the above describeddifficulties are overcome by simple and inexpensive means to improvesubstantially the pumping performance.

According to the present invention, briefly summarised, there isprovided an oil-diaphragm slurry pump in which, in a riser portion ofthe slurry connecting pipe, there is provided a pipe part of largecrosssectional area having an internal volume greater than the suctiondisplacement of the plunger pump of the slurry pump and having aninternal configuration such that the cross-sectional area of the slurryflowpath therewithin is abruptly changed thereby to generate turbulentflow, eddy flow or vortices continually in the slurry flow duringoperation of the slurry pump.

The nature, principle, and utility of the invention will be more clearlyapparent from the following detailed description with respect topreferred examples of em bodiment of the invention when read inconjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the'drawing:

.FIG. 1 is a diagrammatic side elevation, in vertical section, showingthe essential parts of an example of an oil-diaphragm slurry pumpconstituting an embodiment of the invention; and

FIG. Z is a fragmentary, diagrammatic side elevation, in verticalsection, showing the essential parts of another embodirnent of theinvention. 1

DETAILED DESCRIPTION Referring first to FIG. I, the principal componentsof the oil-diaphragm slurry pump illustrated therein are a plunger pump1, a valve box 7, and an oil-diaphragm chamber 5 connected therebetween.

The plunger pump 1 has a cylinder 3 and a plunger 2 operating as areciprocating piston in the cylinder 3 to draw in and expel diaphragmoil. The cylinder 3 is communicatively connected by an oil connectingpipe 4 to the upper part of the oil-diaphragm chamber 5, the lower partof which is communicatively connected by a slurry connecting pipe 6 to amiddle chamber 7a in the valve box 7.

The diaphragm chamber 5 contains in its upper part a diaphragm oil 18,which is integrally communicative with oil in the oil connecting pipe 4and the cylinder 3, and in its lower part with slurry 17, which isintegral with slurry in the slurry connecting pipe 6 and the middlechamber 7a. An interface 19 is naturally formed between the oil 18 andslurry 17 in the oil-diaphragm chamber 5. The chamber 5 is providedthereabove with an oil reservoir tank 15 connected by way of a shut-offvalve 16 to the top of the chamber 5.

The valve box 7 has at its bottom a slurry suction pipe 2 and at its topa slurry discharge or delivery pipe 13. The aforementioned middlechamber 7a is formed between ball valves 10 and 11 operatingcooperatively with respective valve seats 8 and 9' formed on the innerwall surface of the valve box 7. The ball valves 10 and 11 and theirvalve seats operate as: check valves to permit slurry to flow in onlythe delivery direction.

Further description of the slurry pump of the above describedorganization will be omitted since detailed description of theorganization and operation thereof is given in the aforementionedreferences.

In accordance with this invention, the riser part of the slurryconnecting pipe 6 is provided with a largediameter conduit or pipe part14 in which the flowpath cross-section area of the pipe 6 increaseabuptly, and which has a volumetric capacity greater than the suctiondisplacement volume of the plunger pump 1.

During the operation of the slurry pump, the slurry in the connectingpipe undergoes reciprocating flow alternately toward and away from thevalve box 7. As the slurry flows in this manner through the abruptlyexpanded, large-diameter conduit 14, vortices or eddys are formed in theslurry or turbulent flow of the slurry is created, whereby the particlescontained in the slurry are continually maintained in a flloating statewithout settling even when at low flow velocities. Accordingly, cloggingof the pipe 6 due to settling and accumulation of the particles does notoccur. Furthermore, since the volumetric capacity of this large-diameterconduit part 14 is greater than the suction displacement of the plungerpump 1, there is no possibility of air or bubbles tending to beentrained in the slurry being drawn into the diaphragm chamber 5 throughthe connecting pipe 6 and thereby of a lowering in the pump delivery.

Inanother example of this invention as illustrated in FIG. 2, the slurryconnecting pipe 6 is providedin its I riser portion with alarge-diameter pipe part 20, which I has therewithin a plurality ofbaffle plates 21 of shapes similar to orifice plates. These baffleplates 21 function to produce abrupt changes in the flow cross-sectionalarea and, accordingly, to form vortices eddys or turbuwhich theaforedescribed difficulties are overcome. In addition to theaforementioned advantages derived in this invention, the labour ofdeaeration is unnecessary since the infiltration of air into andaccumulation thereof in the oil-diaphragm chamber is prevented, and thepump delivery can be maintained steadily for long periods. Furthermore,since the flow resistance in the slurry connecting pipe is decreased,there is no liquid column separation, whereby generation of noise andvibration is prevented.

We claim:

1. In an oil-diaphragm slurry pump comprising a plunger pump of acertain suction displacement, a valve box for pumping slurry, and anoil-diaphragm chamber communicating by way of an oil path with theplunger pump and communicating with the valve box by way of a slurryconnecting pipe having a riser portion, the improvement wherein saidriser portion has a pipe part of enlarged cross-sectional area, saidpipe part having an internal volume greater than the volume by which theplunger pump makes said suction displacement and also having such aninternal configuration that the cross-sectional area of the slurryflowpath through the pipe part is abruptly and discontinuously changedat least at both ends of the pipe part, said pipe part havingtherewithin baffle plates for generating vortices in the slurry flow inthe pipe part during operation of the slurry pump.

2. An oil-diaphragm slurry pump according to claim 1 in which saidbaffle plates are in the form of orifice plates.

1. In an oil-diaphragm slurry pump comprising a plunger pump of acertain suction displacement, a valve box for pumping slurry, and anoil-diaphragm chamber communicating by way of an oil path with theplunger pump and communicating with the valve box by way of a slurryconnecting pipe having a riser portion, the improvement wherein saidriser portion has a pipe part of enlarged cross-sectional area, saidpipe part having an internal volume greater than the volume by which theplunger pump makes said suction displacement and also having such aninternal configuration that the cross-sectional area of the slurryflowpath through the pipe part is abruptly and discontinuously changedat least at both ends of the pipe part, said pipe part havingtherewithin baffle plates for generating vortices in the slurry flow inthe pipe part during operation of the slurry pump.
 2. An oil-diaphragmslurry pump according to claim 1 in which said baffle plates are in theform of orifice plates.